Alkyl polyglucosides (APGs) are surfactants known for use in the personal care industry, e.g. for hair and skin cleaning and conditioning products. APGs are synthesised from the reaction of glucose and a fatty alcohol. APGs are polymeric in nature and can contain one or more glucoside units. APGs are usually provided as a mixture of products that differ in terms of the extent of polymerisation. Therefore when referring to the degree of polymerisation (dp) for APGs this will be given as the average (mean) degree of polymerisation of the mixture. For example, a 50:50 mixture of an APG with a dp=1 and an APG with a dp=2 will provide an average degree of polymerisation of 1.5.

An APG can be reacted with a functionalising agent to create a functionalised polymer. A cross-linking agent will usually be used in such a reaction to create a ‘cross-polymer’.
Functional groups that can be added include quaternary compounds, phosphates, carboxmethylates, maleates, sulfonates (including hydroxyalkylsulfonates), succinates and sulfosuccinates. The synthesis of these functionalised APGs is described in U.S. Pat. Nos. 6,627,612 and 7,507,399.
Alkoxylated terpenes are primarily used as emulsifiers, solubilisers, wetting agents and low foaming surfactants in agrochemical, home care, institutional and industrial applications. These terpene alkoxylates are obtained by the reaction of the terpene (nopol) with alkoxides such as ethylene oxide, propylene oxide and/or butylene oxide. This is described in, for example, US patent publication 2006/0135683.
A derivative of a terpene alkoxylate can be obtained by reacting the terpene alkoxylate with a functionalising agent. For example, an ether carboxylic acid derivative can be prepared by the reaction of the terpene alkoxylate with sodium monochloroacetate (SMCA) at 80° C. The alkyl ether carboxylate may be prepared using a slight molar excess (1.1-1.2 moles) of SMCA per mole of alkoxylate in the presence of an alkali (NaOH). The resultant mixture can be acidified and washed with water to remove any residual sodium chloride.
It is well known that steel and other metal surfaces can corrode in the presence of aqueous environments; especially acidic aqueous environments such as those found in subterranean wells, which can pass through formations containing high concentrations of corrosive materials such as hydrogen sulphide, carbon dioxide, brine, and the like.
Alloy technology and galvanisation have resulted in materials that can withstand some incidental contact with corrosive environments, but in a number of industrial applications (such as hydrocarbon exploration, recovery and refining, and chemical processing) more prolonged contact with corrosive environments occurs. In particular, during the working life of an oil or gas well various conduits and other components in the production zone encounter considerable acidic corrosion.
Corrosion inhibitors are therefore widely used in oil and gas production wells and pipelines to reduce corrosion of metal components and therefore prevent consequential production equipment failures.
Imidazolines are commonly used as corrosion inhibitors, and are viewed as the industry standard, but are known to have poor aquatic toxicity. Other known corrosion inhibitors for use in oilfields are based on fatty amine, fatty amidoamine or quaternary ammonium chemistries. However, these compounds are also harmful to aquatic species. These known corrosion inhibitors can also exhibit poor biodegradability.
There is therefore a continuing need for corrosion inhibitors, for use in the oil and gas industry and other industrial applications, which have improved aquatic toxicity and biodegradability.